The present invention relates to water dispensers, and more particularly, to a water dispenser for use with a refrigeration apparatus and including an arrangement to prevent dripping or run-on of the water dispenser.
Manufacturers of refrigerators have offered, as a feature of their product, a water dispenser mounted to the exterior of the refrigerator door. Such a water dispenser is usually combined with a water reservoir, remotely located within the refrigerated compartment, to provide ready access to chilled water without the need to open the refrigerator door. A conduit extends between the water reservoir and the water spout from which the water is directed into a vessel such as a drinking glass. A valve, typically operated by a lever arm pressed by a glass is used to control the dispensing of water.
A common problem, associated with refrigerator dispenser mechanisms, is run-on. Run-on is dripping of water from the tube while it is not in use. There are several causes of run-on. The water reservoir expands when pressurized and contracts when de-pressurized. This causes water to run for a short time immediately after removing the glass. This effect is enhanced by compressible air bubbles trapped in the water reservoir. Dissolved air in the water can come out of solution at the low pressures in the reservoir. The added volume causes run-on. Water reservoirs sometimes freeze. The expanding ice displaces water causing dripping. All of these effects are caused by a volumetric displacement of water somewhere in the dispensing system after the water valve is turned off.
The present invention provides an arrangement for preventing dripping from the water spout in a water dispenser for a refrigerator after the shut off valve has been closed. Immediately upon the shut off valve being closed, any water in the conduit from the point of the shut off valve to the water dispenser is withdrawn back into the conduit by a suction force, thereby preventing any dripping from the water spout. In an embodiment, a reservoir is provided which communicates with the conduit and which is maintained below atmospheric pressure during a flow of water through the conduit such that when the valve is closed, any water remaining in the conduit from the valve to the water spout is drawn into the reservoir area by a suction action and is held there until a further dispensing of water occurs.
In an embodiment, the invention comprises the use of a rigid plastic tube which is surrounded by a vacuum chamber. A Venturi type vacuum device is built into the plastic tube so that when water passes through it, a vacuum is created in the surrounding chamber. When the water is turned off, water flows into the vacuum chamber due to the reduced pressure. This creates a volumetric buffer for any type of run-on that may occur. The vacuum chamber may be made of a rigid material if a small buffer is desired or an elastic material for a larger buffer volume. In the rigid design, a pressure lower than the vapor pressure of water is required to create the buffer. In the elastic design, the vacuum chamber material could have some degree of shape memory. When the water is flowing, the elastic vacuum chamber collapses due to the reduced pressure inside. When the water is turned off, it would expand, creating a larger buffer volume. There should be sufficient internal volume in the dispensing conduit, in the direction of flow, downstream of the vacuum chamber, to prevent external air from entering the vacuum chamber.